Osborne Diamond was a Manticoran citizen and an officer of the Royal Manticoran Navy. Holding the rank of Lieutenant Commander, he served as Commander Eleanor Hope's executive officer aboard the heavy cruiser HMS Vigilant. When Hope refused to participate in Captain Aivars Terekhov's attack on the Monica System, she was relieved of command and Diamond took over as CO of Vigilant. He led the ship into the fight and was killed in the Battle of Monica. (SI1)